title: The type I inositol 1,4,5-trisphosphate receptor interacts with protein 4.1N to mediate neurite formation through intracellular Ca waves.
abstract: Ca(2+) waves are an important mechanism for encoding Ca(2+) signaling information, but the molecular basis for wave formation and how this regulates neuronal function is not entirely understood. Using nerve growth factor-differentiated PC12 cells as a model system, we investigated the interaction between the type I inositol 1,4,5-trisphosphate receptor (IP3R1) and the cytoskeletal linker, protein 4.1N, to examine the relationship between Ca(2+) wave formation and neurite development. This was examined using RNAi and overexpressed dominant negative binding regions of each protein. Confocal microscopy was used to monitor neurite formation and Ca(2+) waves. Knockdown of IP3R1 or 4.1N attenuated neurite formation, as did binding regions of IP3R1 and 4.1N, which colocalized with endogenous 4.1N and IP3R1, respectively. Upon stimulation with the IP3-producing agonist carbachol, both RNAi and dominant negative molecules shifted signaling events from waves to homogeneous patterns of Ca(2+) release. These findings provide evidence that IP3R1 localization, via protein 4.1N, is necessary for Ca(2+) wave formation, which in turn mediates neurite formation.
authors.affiliation: Cell Biology Department, Yale University, New Haven, CT 06520-8019, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Fiedler
authors.forename: Michael H
authors.initials: MH
authors.lastname: Nathanson
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D020013:Calcium Signaling / Q000502:physiology*; D002217:Carbachol / Q000494:pharmacology; D002454:Cell Differentiation / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics / Q000378:metabolism*; D007424:Intracellular Fluid / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism* / Q000648:ultrastructure; D055495:Neurogenesis / Q000502:physiology; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D017434:Protein Structure, Tertiary / Q000235:genetics; D034622:RNA Interference / Q000502:physiology; D051381:Rats
chemical_list: D003598:Cytoskeletal Proteins; C120904:Epb41l1 protein, rat; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009479:Neuropeptides; C120557:erythrocyte membrane protein band 4.1-like 1; D002217:Carbachol